This invention relates generally to a lamp socket, and more specifically, to a lamp socket that stabilizes a lamp or bulb within the socket.
A most basic requirement of the many different vehicle lamp socket designs in use today, is the requirement that the lamp socket secure the lamp against damage, including damage from vibration that occurs during operation of the vehicle. At least some lamp sockets retain the lamp in a manner that allows for an amount of lateral lamp movement within the socket. Such lateral movement of the lamp within the socket is undesirable in that it adversely affects the interface between the lamp lead wires and the lamp socket contacts and is a common source of failure in the lighting system. In one approach to retaining a wedge base lamp, U.S. Pat. No. 5,197,187 describes a lamp socket wherein the terminal contacts include beams that retain a lamp base in the socket. U.S. Published Patent Application 20040132336 and its parent, Published Application 20030068929 describe lamp sockets that include features that, in conjunction with terminal contacts, align, stabilize, and retain the lamps in the sockets.
A shortcoming associated with the aforementioned socket designs is that the terminal contacts alone do not provide sufficient stability for the lamp. As a result, these designs rely on features in the plastic socket housing, such as flexible supports, to provide bulb stabilization. Over time, loss of contact pressure, and fretting corrosion due to plastic retainer softening may compromise the bulb stabilization features of the housing, and may also bring about lamp failure. These effects are accelerated when the socket is exposed to lamp operating temperatures. Some socket designs also incorporate a retainer mechanism to facilitate stabilization of the lamp. But, the retainers typically provide only a point engagement with the lamp, and thus, are not particularly effective.
A need remains for a cost effective lamp socket that provides lamp retention, and lamp stabilization that render the lamp socket suitable for use in the often harsh environment associated with motor vehicle lighting.